Radiation in the terahertz (THz) frequency range has certain properties that make it useful in applications such as spectroscopy, medical and security imaging, process monitoring and inspection in manufacturing, and remote sensing. This is because THz radiation can safely pass through living organisms and materials such as clothing fabrics, plastics, paper materials, masonry, and ceramics. In short, the THz radiation interacts with such materials causing certain information signals to be generated, which in turn can be used to form multi-dimensional images of the materials. In addition, measuring absorption of THz radiation as a function of wavelength allows for spectroscopic imaging and chemical composition detection.
However, there are problems associated with THz radiation generation. For instance, because of frequency conversion techniques, the Manley-Rowe conditions limit conversion efficiency: As a result, conventional THz generation techniques limit terahertz conversion efficiency and output power achievable. What is needed, therefore, are techniques for efficient THz radiation generation.